Recently, a cellular system of fourth generation (4G) is discussed to achieve further improvements on the performance of wireless communication. In the 4G, relay technology, carrier aggregation, and Coordinated Multiple Point transmission and reception (CoMP) technology are paid attention.
The relay technology is a technology by which a relay node relays communication between a base station (for instance, a macrocell base station) and a communication terminal, and is important in improving cell-edge throughput of the base station. Moreover, the carrier aggregation is a technology that extends a usage bandwidth (for instance, 20 MHz*5=100 MHz) and achieves an improvement in maximum throughput by collectively treating a plurality of frequency bands that have a bandwidth of 20 MHz. Moreover, the CoMP is a technology by which a plurality of base stations called a CoMP set cooperates to communicate data with a communication terminal, and can expand the coverage that can support communication at high data rates. The CoMP is disclosed in Patent Document 1, for example.
Moreover, in the 4G, it is being discussed to improve the coverage by introducing base stations other than macro-eNodeBs, for example, by introducing Home eNodeBs (femtocell base stations, micro-base stations for mobile phones), remote radio heads (RRHs), and pico-eNodeBs.